Means for and method of wave transmission



' J. MILLS.

MEANS FOR AND METHOD OF WAVE TRANSMISSION.

APPLICATION FILED DEC. 30. 1916- 1,412,567. Patented Apr. 11, 1922.

lm VPII fol 5 John Mills.

UNITED STATES PATENT OFFICE.

JOHN MILLS, OF WYOMING, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC CO]!!- IPANY, INCORRORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

MEANS FOR AND METHOD OF .WAVE TRANSMISSION.

Specification of Letters Patent. Patented Apr. 11, 1922.

Application filed December 30, 1916. Serial No. 139,741.

To aZ Z whom it may concern:

Be it known that I, JOHN MILLS, a citizen of the United States, residing at Wyoming, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in. Means for and Methods of Wave. Transmission, of which the following is a full, clear, concise, and

exact description.

10 This invention relates to elimination or reduction of static or other similar interference.

It is Well-known that when an impulsive .orstatic disturbance is received by a high 15.frequency signaling system, a disturbing noise is produced in the telephone receiver associated with the receiving system.

The present invention has for an object to provide a method and means for elimiilating the noise in the receiver due to the reception of d sturbing waves of static or other origin. This is accomplished, first, by converting 'the high frequency signal and disturbing currents into audio frequency signal currents, which will have superimposed thereon audible frequency noise currents, due to the disturbing waves, and second,'by suppressing the audible frequency noise currents.

In a more specific aspect the invention provides for receiving the high frequency signal and impulsive disturbances in a circuit having a single natural period of vibration, as distinguished from prior receiving circuits, having two natural periods, which are differentially related to the signal receiving device, as in the patent. to De Forest. No. 759,216. In the present invention the elimination of the audio frequency disturbing currents depends upon the difference in the character ofaudio disturbing currents and the audio signal currents, and advantage is taken of this difference in character to suppress the fOI I1'161'.- With reference to the v audio frequency, the duration of the dis turbance due to a static wave or other wave having a similar wave-form is so short that it is substantially a pulse. It is well known that when an'electromotive pulse strikes a resonant network, such as a filter of the well known Campbell type,. curr'ents of natural oscillation are .established corresponding to the periods of ,free vibration of the resonant network orfilter. According to the present conducting.

coupled in a tion is not restricted to the use of this par invention the audio"frequency currents are supplied to a filter which has its modes of free vibration critically damped, so that pulses which a filter receives is reduced by means of the damping, and a plurality of filters are provided in order that there may be a sufiicient reductioiu Audio frequency signaling currents, however, acting'as forced oscillations, are transmitted through the filters sufficiently well, so that the signal currents are selectively received free from disl turbances due to the interfering currents.

For a detailed description of the invention, reference may be made to the drawing, in which the figure shows diagrammatically a system embodying the invention.

0 aid in reading the drawings each audion is provided with an auxiliary reference letter having the following significance: Gzgenerator, Dzdetector, U: unilaterally Referring to the drawing, the antenna 1 is coupled by means of the transformer 2 to the input circuit of a detector 3, which may be of the audion type as shown. The input circuit of thedetector 3 is tuned by means of the variable condenser 4 to the; high frequency torbe received. The antenna is very loosely coupled to the circuitcontaining the condenser 4. As a single resonant circuit is provided between the antenna 1 and the detector 3, it will be apparent that, under these circumstances, this. receiving system has sub-- stantially one high frequency natural period of vibration. Coupled to the input circuit of the detector 3, by means of the circuit 5, is a generator 6' of high frequency oscillations. This generator 6 is shown as comprising an audi'on having its input and output circuits known manner, but the inventicular type of generator. For receiving telegra h signals, the generator 6 supplies oscillations of a frequency different from the frequency to which the input circuit of the detector 3 is resonant. This is commonly ,known as heterodyne reception. If it is desired to receive wireless telephone messages,

the generator 6 supplies oscillations of the -same frequency as that for which the input the audio frequency disturbing currents. Asjf. described above, this means 'COIIIPIISBS a" plurality of filters ,-F F F 3 and F", of

the well-known Campbell type. As shown,

each one of these filters has three sections,

. although each filter may have a single section only or may have more than three sections if desired. Furthermore, the filters need not all have the same number of sec-' tions. Each of the filters or resonant networks having three sections will have three modes or periods of free vibration, the latter, howev'r,bein'g critically damped by means of the resistance elements 8, 9, 10 and 11. The natural frequencies of the filters may have any desired values within the audio frequency range, .The values of the electrical constants of the filtersmay assume a great variety of different values, which may be computed by '.well-known formulae. The maximum amplitude of any natural oscillation establishedin the first section of any ifilter= will be. inversely as the inductance of the filter element regardless of the number of sections, so that several sectional.

filters instead of a single filter having alargfr number of sections is to be preferred. 11

order to prevent reaction between the 'filter F and the circuits between it andthe detector 3, a unilateral device 12, which may be of the audion type as shown, is provided. This unilateral device 12 has its input circuit tuned by means of the condenser 13 to the audio frequency range to be received, whereby high frequency currents are suppressed and prevented from reaching the filters. The circuit containing condenser 13 may be flatly tuned by means of resistance, particularly where it is necessary to cover the audible range of speech as in telephony. It isyto be noted that the resistance 8 is included in the output circuit of the unilateral element 12 and the resistance 11 is in the input circuit of the unilateral device 1 1. Other unilateral elements, 14, between filters F and F 15, between filters F and F 16, between filters F and F; 17, between the signaling device 7 and the filter F, are provided for similar purpose, i. e., to transmit current from the detector 3 to the signaling device 7 unilaterally and to prevent reaction between the various filters and networks shown.

As described above, it will be apparent that the audio frequency interfering currents supplied bythe detector 3 will be converted into pulses by means of the filters 1*, F F 3 and. F which have their natural vice 7 to the exclusion of the interfering currents.

lVhat is claimed is:

1. The method of eliminating static disturbance in a receiving circuit having a single naturalhigh frequency period which consists in converting the high frequency currents into audio frequency noise and signal currents, and successively attenuating-said noise currents.

2. In a wave transmission system, a plurally branched electrical network including inductance and capacity elements, means for supplying electrical energy to said network comprising an" ohmic resistance included therein across which input potential differences are established, an ohmic resistance, included therein across which potential differences to be derived from said network are established, and a unidirectionally conducting device connected across said lastmentioned resistance.

- 3. A high frequency receiving circuit havcomprising a resistance across which potentialsto be applied to said network are impressed, and another of sald sections including a resistance across which is directly connected said wave-responsive device.

In a receiving system, two thermionic devices, means connected between said devices comprising a recurrent network of a pluralityof sections, each closed path in said n twork including aresistance of sufiicient value to prevent free oscillations of a period determined by the constants/of any path in said network.

6. In a wave transmission system, a plurally branched electrical network including inductance and capacity elements, an ohmic resistance in said network connected in the output circuit of 'a) space discharge device 130 for applying input energy to said network, and an ohmic resistance in said network constituting means for connecting said network to a device to which energy is to be supplied.

7. In a receiving system for eliminating static disturbances a network having a plurality of resonant sections, a resistance in each of said sections, two thermionic devices, eachhaving an, input circuit and an output circuit, one of said resistances being ;in the input circuit of one of said thermionic devices, the other of said resistances being in the output circuit of the, other of said thermionic devices, and said network being located between said devices.

8. In a wave receiving system, a plurality of networks each consisting of a plurality of sect-ions including inductance, capacity, and resistance, each network being adapted to transfer energy with equal facility from its input to its output terminals and vice versa, and a thermionicdevice adapted to connect the output terminals of one network with the input terminals of a succeeding network. 9. In. a receiving system for eliminating static disturbances, an energy transferring conductive system having a plurality of cir- "ing device, and a circuit for connecting .said 1 cuits, ,each including inductance, capacity and resistance, andhaving a plurality of degrees of freedom, and a unidirectionally conducting device between adjacent circuits of said conductive system. for preventing reaction between said circuits.

10. A receiving system comprising a hi h frequency line, a detector adapted to e supplied with energy from said line, a signaling device, and a circuit for connecting said device to said detector, said circuit comprising "a plurality of, sectional networks,

each section of at least one of said networks including resistance, inductance and ca-- p cefrequency line, a detector adapted to be .sup plied with energy from said line, a signaldevice to said detector, said circuit 'comprising a plurality of critically; damped resonant circuits, and means for preventing reaction between said resonant'ci'rcuits.

12. A receiving system comprising a high frequency line, a detector adapted to be sup-- plied with energys-from said line, a signaling device, a circuit forconnecting said device to said detector,sa1d circuit lncludlng a luralit of circuits each having a plura lty of egrees of freedom, and means 'for preventing the reaction of said circuits upon each other.

13. A receiving system comprising a; re-

ceiving conductor, a detector adapted to be supplied with energy from said conductor,

a signaling device and a circuit for connect- ,either direction between its input terminals and itsoutput terminals, and a thermionic device between adjacent circuits for preventing\ reaction therebetween.

14. In a wave transmission system, a plurally branched electrical network including inductance and capacity elements, an ohmic resistance connecting two points in said net work, connections from two points on said resistance to the output electrodes of a space discharge repeater, an ohmic resistance connecting, two other points in said network, and connections from two points on said last-mentioned resistance -to the input electrodes of a space discharge repeater.

15. A wave transmitting system including a plurality of the combinations'described in claim 14 arranged in tandem.

16. A system comprising an electrical network consisting of a plurality of similar recurring sections, each'section including inductance and capacity elements, an ohmic resistance in one section for deriving wave energy from said network, a space discharge repeater having its output circuit connected to the first of said resistances and a second space discharge repeater having its input circuit connected to the second of said resistances.

17 A radio receiving. system comprising means for supplying and combining waves from a local source with received waves, and a periodic plurally branched electrical network having its branches conductively connected and comprising a plurality of identical closed paths each containing inductance and capacity, means for supplying the combined waves to said network, and means for receiving waves transmitted through said network.

'18. A receivlng system comprisingmeans forsupplying and combining waves from a of plurally branched electrical network's each containing a plurality of closed paths including inductance and capacity elements, an asymmetrically conducting device between each adjacent pair of said networks, means for supplying the combined waves to the first -of. said networks and means for receiving waves transmitted through the last of said networks. 7

19. The method of receiving radio signals at a receiving station which comprises combininglocally-generated waves with the reocal source with received waves, a plurality 1 ceived waves, transmitting the resultant,

waves through a plurality of wave selecting circuitsiarranged in tandem, preventing the reaction of said circuits upon each other in a reverse direction through said circuits, and

means for combining locally generated waves with received waves and means for passing the resultant waves through a system including a tandem arrangement of the following elements in the order named: An asymmetrically conducting repeater, a/periodic electrical network comprisin a plurality of closed sections including inductance and capacity, and an asymmetrically conductin repeater.

21. translation of electrical waves at a'receiving station comprising receiving desired and disturbing waves together, combinin other waves of a definite frequency therewith, selectively transmitting the resultant waves through a selective electrical network, amplifying the selectively said network, and selectively receiving and translating the amplified output waves into other than electrical energy at said station. 22. A receivin station comprisingmeans for combining ot er waves of a definite frequency and desired amplitude with received waves, a detector for detectin the combined waves, an asymmetrically con ucting device, a selective network,-means for passing the detected waves in succession through said asymmetrically conductin device and said selective network and a l ow frequency re sponsive device controlled by the output of said network.

23. A receiving station comprising in successive tandem arrangement at said station means for combiningother waves of a defimite frequency and desired amplitude with received signaling and interfering waves, a

detector for detecting the combined waves,

. other energy,

a filter for selecting the detected waves, a

low frequency wave controlled device at said station for converting electrical energy into and an asymmetrically conducting repeater for transferring the waves passed by said filter to said devlce.

24. A receiving system comprising means for combining other waves with received signaling and interfering waves and detecting the combined waves, a recurrent network comprising series and shunt re'actance elements, two unidirectionally energy transhe method of selective reception and transmitted output of 1,412,5err p ferring devices between which said network is connected, and means for supplying the combined detected waves to the first of said devices.

25. The method of selective reception comprising first mixing with the received waves otherwaves of desired amplitude and constant frequency and successively amplisignal indicating device, a selective circuit fpr conducting the detected waves to said signal indicating device, and an unsymmetrically conducting device between said last mentioned selective circuit and said indicat- 1ng device.-

'28. A receiving system comprising means for combining locally generated waves with received waves, means for detecting the combined waves, a plurality of heavily damped selective circuits, an asymmetrically conducing device between each adjacent pair of select ve circuits, and means for passing the detected waves through said selective circuits and each conductive device interposed betweenadjacent pairs thereof.

29. A receiving system comprising means for combining other waves of a definite frequency and desired amplitude with received waves, a wave distorting device for translating the combined waves, an asymmetrically conducting device, a selective iterative .electrical network, and means for passing the resultantwaves in succession through said asymmetrically conducting device and said network. i

In witness whereof, I hereunto subscribe my name this 29th day of December A. D

9 JOHN MILLS. 

